"I think Brian is the greatest art critic of his generation and when I was editor of the Evening Standard from 2002 to 2009, I always defended him," Wadley added.

"Most of London's art establishment lobbied me constantly to dismiss him; and their dislike was magnified by the management who wanted him sacked because they thought he was pretentious and out of touch with the modern world, with an absurdly generous contract."

Sewell, 82, is considered an institution in the art world despite his conservatism and distaste for popular culture including what he sees as the glorification of modern conceptual art by the Turner prize.

He is also an institution in the Evening Standard and is in the running for the title of the UK's longest-serving columnist, having been the newspaper's art critic for 29 years.

Wadley said she was a huge fan and dealt with him sensitively. "Throughout I protected him and even insisted that he was paid his full salary when he stopped writing his weekly op-ed column to concentrate all his energies on his art criticism for the paper.

"Of course I never told him how unpopular he was. On the contrary I always supported him and enjoyed the controversy he stirred up."

Among the editors slated are his Tatler bosses Libby Purves ("an ample frump") and Emma Soames ("an unloved termagant ... overheard to remark that I thought her as sexually attractive as a saucepan of boiled socks, it was time for me to leave").

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